How a 'hum' from space helped scientists show the universe is in constant movement

Separate international teams of scientists announced they observed a constant "hum" of gravitational waves that fills space. The discovery is much more important than it seems.

Gravitational waves are wrinkles or waves in the fabric of the universe caused by massive celestial bodies that move through space like waves after throwing something in the water.

Albert Einstein predicted the existence of gravitational waves in his theory of relativity. That explains how matter interacts with time and space.

According to the theory, time and space can be considered a fabric. Imagine an elastic piece of fabric tensed in the air by four poles.

If an object, like a planet or a massive black hole, moves through the time-space, it creates waves. It also explains how the presence of another object can affect the trajectory of a moving one.

In 2015, the Laser Interferometer Gravitational-Wave Observatory (LIGO) observed these "waves" for the first time, providing crucial support to Einstein's theory.

But now, scientists have reported "hearing" a different kind of hum: the gravitational wave background.

The constant hum, explains an article from Smithsonian magazine, could come from pairs of supermassive black holes, suggesting that the fabric is constantly moving.

Adam Frank, from The Atlantic magazine, compares the hum with the background noises of a city: distant horns, construction, traffic, voices...

It shows how the universe is in continuous movement and how that motion creates constant gravitational waves, like a permanent vibration in the fabric.

"These observations reveal a rolling, noisy universe alive with the cosmic symphony of gravitational waves," Sean Jones of the National Science Foundation told the media in a briefing about the discovery.

According to The Atlantic, the sounds can come from distant events, like the creation of galaxies or even the universe's origin. The energy released in the Big Bag would have made big waves.

The discovery was documented in several papers by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) and published in Astrophysical Journal Letters.

Separate teams from Europe, India, China, and Australia also released research papers that describe the same universal hum heard in different observatories.

However, the chances of it being a random coincidence is still too high for scientists to consider the hum a discovery, explains The New York Times.

But scientists hope they will find more evidence of the gravitational wave background in the future. "We'll get there," Chiara Mingarelli, a member of NANOGrav, told the newspaper.